The invention is directed to an electromagnetic relay having a housing, terminal elements guided out of the housing, and a control module in the form of an integrated circuit arranged in the housing.
It is already known in an electromagnetic relay to accommodate a control module in an outwardly open chamber of the bottom plate, the terminal pins of this control module being arranged parallel to the terminal pins of the relay (DE 36 14 919 C2). As long as this known relay is operated in normal ambient temperatures, the control module having electronic components will also not heat to an impermissible degree, so that the function is guaranteed. Given this and other known relays having integrated circuits arranged within the housing, however, reliable operation has previously only been guaranteed when the thermal stress due to coil heating and contacts as well as ambient temperature does not proceed beyond the loadability of the electronic components. Such integrated circuits can only be loaded up to an upper limit temperature of 150.degree. C. Temperatures proceeding beyond this considerably shorten the useful life of these components.
Given relays for specific purposes, however, there is the need for a regulation of the control voltage or of the coil current given a simultaneously high thermal loading due both to high switching currents in the interior of the relay as well as due to high ambient temperatures. A typical application for such a relay is a motor vehicle wherein the contacts must carry extremely high currents at low voltages, while the ambient temperature fluctuates greatly and, for example, can amount to up to 125.degree. C. When the self-heating of the relay is then added, thermal loads up to 200.degree. C. thus result, temperatures which an integrated circuit cannot withstand. A regulation of the control voltage, however, is desirable or required precisely because of the great temperature fluctuations. Thus, one would also like to accommodate the control modules in the relay housing in this case as well as for saving space and assembly work.